The invention relates to a clamping device, particularly for the cutting tools of machine tools, having a tool block which can be affixed by clamping means to the clamping plate of a tool carriage or the like, and which has first guidance means that cooperates with second guidance means of the clamping plate.
Such clamping devices are known and serve, for example, to quickly and easily exchange or set the cutting tools of automatic lathes and to clamp these accurately in position.
For setting a tool attached to the tool block, clamping devices are generally provided with two or more parallel guide rails mounted on the clamping plate, on which the tool block is slidably displaceable via guidance grooves. To clamp the tool block in place, there are generally used one or more T-head bolts, which extend through the tool block and are screwed tight by nuts. The T-head bolts are slidably located between the guide rails in the clamping plate.
This arrangement has the drawback that the guide rails, in addition to guiding the tool block, also provide the bearing surfaces for transmitting the forces created by the clamping and the cutting. Because clamping forces are exerted between the bearing surfaces of the tool block, there arise substantial bending moments, which lead to deformation of the block, of the clamping plate, and of the underlying tool carriage, and therefore to undesired changes in its guidance system.
A further drawback of this arrangement is that the specific surface pressures between the guide rails and the tool block are very high during clamping.
To prevent bending moments of the tool block and high surface pressures between the block and the guidance track, it is also known to provide the tool block with a shaped clamping surface which, together with a correspondingly-shaped clamping surface of the clamping plate, provides a guide for the setting of the tool block. When clamped, the block then bears uniformly over its whole clamping surface against the clamping plate, so that the clamping forces are evenly distributed and there occur no deformations of the tool block and no high surface pressures between the clamping surfaces of the tool block and the clamping plate.
However, this arrangement has the drawback that the clamping surfaces of the tool block and of the clamping plate have to be manufactured with exceptionally high precision in order to fit well together, because otherwise there is not achieved complete freedom from "play" between the two machine tool components, or else the tool block's clamping surface cannot bear fully against the clamping plate so that undesirable, high surface pressures between the clamping surfaces are again encountered. In addition, these clamping surfaces must always be cleaned exceptionally thoroughly.